1 70 



COPEPODS OF LAST CRUISE OF CARNEGIE 



nated as belonging to any particular zone. The species are 

 all very small, with both fifth legs lacking in the female and 

 the right one in the male. 



illff 



Chart i. Daytime vertical distribution of species of Acio- 

 Cdlaiius: (i) gibber, (2) gracilis, (3) longicornis, (4) moiiachtis. 

 The four species were well distributed at all three depths. Three 

 of them were more abundant in the 50-meter tow than in either 

 of the other tows, but the fourth was found at the surface not 

 only more often but also in greater abundance. 



Acrocalanus gibber Cjiesbrecht 



[Acroailanus gibber Giesbrecht, Atti R. Accad. Lincei, Rome, 

 ser. 4, vol. 4, sem. 2, p. 332, 1888; Fauna und Flora des 

 Golfes von Neapel, vol. 19, pp. 171, 175, pi. 6, fig. 32, 1892.] 



Each species of the genus shows very prominent gaps in 

 its distribution, those for the present species including stations 

 44 to 54, 59 to 63, 68 to 91, 117 to 131, all inclusive. It was 

 found in 9 nocturnal and 29 diurnal surface tows, 25 50- 

 meter tows, and 22 loo-meter tows. It is thus apparently in- 

 different to light, and this conclusion is strengthened by the 

 fact that it is found frequently at the surface, at any two of 

 the depths, or even at all three. The surface records not only 

 are more numerous than those from the other tows, but also 

 indicate a larger number of specimens. 



Acrocalanus gracilis Cjiesbrecht 



[Acrocalanus gracilis Giesbrecht, Atti R. Accad. Lincei, Rome, 

 ser. 4, vol. 4, sem. 2, p. 332, 18S8; Fauna und Flora des Golfes 

 von Neapel, vol. 19, pp. 171, 175, pi. 6, fig. 27, 1892.] 



More widely distributed than the preceding species, but 

 not found from stations 71 to 77 inclusive, with a few other 

 gaps of one or two localities only. This species was present 

 in 31 nocturnal and 75 diurnal surface tows, 78 50-meter 

 tows, and 75 loo-meter tows, and in the vertical tow from 

 TOGO meters, station 64. In the daytime, therefore, the vertical 

 distribution at the three depths was exceptionally even, but 

 the abundance records in the surface tows were slightly 

 higher than the others. 



Acrocalanus longicornis Giesbrecht 



[Acrocalanus longicornis Giesbrecht, Atti R. Accad. Lincei, 

 Rome, ser. 4, vol. 4, sem. 2, p. 332, 1888; Fauna und Flora 

 des Golfes von Neapel, vol. ig, pp. 171, 175, pi. 6, figs. 25, 

 33; pi. 10, figs. 34, 36, 39, 1892.] 



The gaps in the distribution of this species extend from 

 stations 42 to 51, 55 to 65, 67 to 87, and 114 to 134, inclusive. 

 This species was taken in i nocturnal and 19 diurnal surface 

 tows, 26 50-meter tows, and 13 loo-meter tows. Here, then, 

 the 50-meter tow definitely surpasses either of the others, and 

 there is a marked contrast between the i nocturnal surface 



tow and the 31 for the previous species. This species has been 

 recorded from the Atlantic and Indian oceans and the Red 

 Sea as well as from the Pacific, and its absence from the 

 North Atlantic in the present plankton is noteworthy. 



Acrocalanus monachus Giesbrecht 



[Acrocalanus monachus Giesbrecht, Atti R. Accad. Lincei, 

 Rome, ser. 4, vol. 4, sem. 2, p. 333, 1888; Fauna und Flora 

 des Golfes von Neapel, vol. 19, pp. 171, 175, pi. 6, figs. 26, 

 31; pi. 10, fig. 38, 1892.] 



From station 36 to 86 this species was present only in soli- 

 tary localities; from 88 to 107 it was present at every station 

 e.xcept two, and from 108 to 157 it was again found only at 

 isolated stations, making it the least common of the four 

 species. The forehead is very high, projects forward, and is 

 acutely rounded at the anterior corner, which in the present 

 material was nearly always white, facilitating the identifica- 

 tion of the species. It was found in 2 nocturnal and 11 diurnal 

 surface tows, 32 50-meter tows, and 17 100-meter tows. Here 

 again a majority of the specimens manifested a definite 

 preference for the 50-meter tow. 



Genus AEGISTHUS Giesbrecht, 1891 

 Aegisthus spinulosus Farran 



[Aegisthus spinulosus Farran, Ann. Rept. Fisheries, Ireland, 

 1902-03, pt. 2, app. 2, pp. 46, 47, pi. 12, figs. 8-14; pi. 13, 

 figs. 1-4, 1905.] 



Found only at 9 localities in the eastern Pacific and at i 

 station north of the Samoan Islands. It was captured in 3 

 nocturnal and 3 diurnal surface tows, 2 50-meter tows, and 

 2 100-meter tows. These meager records do not warrant any 

 general conclusion except the negative one that this species 

 does not always migrate downward in the daytime. 



Genus AETIDEUS Brady, 1883 

 Aetideus armatus (Boeck) 



[Pseudocalanus armatus Boeck, Forhandl. Vidensk. Sclsk. 

 Christiania, vol. 14, p. 38, 1872.] 



Well distributed in the Sargasso and Caribbean regions, 

 but quite gregarious in the Pacific and limited to a few 

 localities in each of four regions: the eastern tropical, north 

 of the Samoan Islands, north of the Caroline Islands, and 

 north of the Hawaiian Islands. It was taken in i nocturnal 

 surface tow, 10 50-meter tows, and 41 loo-meter tows, but 

 was nowhere abundant, more than half the records being 

 expressed in numerals. Thus it is definitely negative to light 

 but comes to the surface sometimes during the night. 



Genus AMALLOPHORA T. Scott, 1894 



Amallophora typica T. Scott 



(Figure i) 



[Amallophora typica T. Scott, Trans. Linn. Soc. London, ser. 2, 

 Zool., vol. 6, pt. I, p. 54, pi. 3, figs. 39-46; pl- 4' figs. I--1. 

 1894.] 



Two females were obtained in the vertical haul from a 

 depth of 1000 meters at station 64, and these constitute the 



